A calibration mixture contains a precise, known quantity of a component gas, or component gases, and is typically used to verify a concentration reading from an analyzer or similar equipment. In some instances, a precise concentration of a liquid component is vaporized and blended into the mixture, so that the liquid component may also be used for calibration, or similar purposes. The concentration of the liquid component, in this instance, must be known within a precise range. Typically, the concentration of the liquid component in the mixture is sufficiently low, so that the liquid component remains vaporized at a given temperature and pressure within a storage vessel, such as a cylinder.
The individual cylinders filled with the final blended mixture must be analyzed to assure integrity of each individual cylinder, and to assure that the concentration of the components are within an acceptable range. Typically, a batch filling process is used to fill the individual cylinders with the final blended mixture. Often, each individual cylinder is separately and individually analyzed after the filling process, which is time consuming and expensive. If the final blended mixture does not contain the desired concentration of components, several of the cylinders may be filled with an incorrect mixture before realizing the error. Further, with the batch filling process, a cylinder may be contaminated during the lag time between evacuating the cylinder and filling the cylinder with the final blended mixture.
A goal of the present invention is to provide a system for continuously blending a liquid component in a gas mixture that allows for constant analysis and adjustment during the filling of a plurality of cylinders. A further goal of the invention is to provide an accurate and economical system for continuously filling a plurality of cylinders with a final blended mixture, which comprises at least one gas component and at least one component which is a liquid at ambient temperature and pressure.